Kiyoharu Nakano

Risks and Benefits of Combined Maze Procedure for Atrial Fibrillation Associated With Organic Heart Disease

OBJECTIVES This study sought to identify the risks and benefits of adding the maze procedure in patients with atrial fibrillation (AF) undergoing operation for underlying organic cardiac disorders. BACKGROUND Persistent AF often leaves patients symptomatic even after otherwise successful cardiac surgery. METHODS Fifty-one patients undergoing valvular operation and the maze procedure (n = 43) or repair of congenital anomalies (n = 8) combined with the maze procedure were compared with 51 patients (control group) matched for underlying diseases and procedures except for the maze operation. Each group, including 31 patients with a concomitant tricuspid annuloplasty and 12 undergoing reoperation, were similar in age, duration of arrhythmia, degree of cardiomegaly and New York Heart Association functional class. RESULTS Patients undergoing the maze procedure had longer cardiopulmonary bypass time (213 vs. 144 min, p < 0.0001), longer cardiac arrest (134 vs. 93 min, p < 0.0001) and greater blood loss with longer respiratory care (39 vs. 18 h p = 0.021) and intensive care unit stay but no mortality. No significant differences were found in catecholamine or transfusion requirements immediately after operation. Sustained AF was much less frequent in the maze group (12% at 1 year) than the control group (86%, p < 0.0001), with an average follow-up period of 32 months (range 25 to 42). Atrial contraction was documented in 41 (80%) and 40 (78%) patients for right and left ventricular filling, respectively, after the maze procedure, resulting in a significantly smaller cardiac size and improved functional capacity. Medication was discontinued in seven patients in the maze group compared with two in the control group. CONCLUSIONS Improved restoration of atrial rhythm and contraction with combined maze operation appeared to justify the increased operative time and complexity and postoperative care.

Modified Maze Procedure for Patients With Atrial Fibrillation Undergoing Simultaneous Open Heart Surgery

BACKGROUND Persistent atrial fibrillation (AF) leaves patients symptomatic and at increased risk of thromboembolism even after otherwise successful cardiac surgery. METHODS AND RESULTS To treat AF secondary to cardiac lesions requiring surgery, we combined a modified maze procedure in 101 patients simultaneously undergoing valvular procedures (87), repair of congenital anomalies (12), and other procedures (2), including 24 repeat operations. Duration of AF varied from 0.1 to 30 years (average +/- SD, 8.8 +/- 7.0 years); the f-wave voltage ranged from 0 to 0.45 mV (0.15 +/- 0.09 mV); and cardiothoracic ratio varied from 40% to 99% (63 +/- 9%). Aortic cross-clamp time varied from 75 to 229 minutes (138 +/- 31 minutes), with bypass time ranging from 119 to 326 minutes (217 +/- 42 minutes). There were two early deaths (2%), no late deaths, and one episode of transient neurological ischemic attack in follow-up ranging from 1.0 to 3.1 years, for a total of 190 patient-years. Postoperative rhythms were sinus in 83 patients (82%), junctional in 4 (4%), and persistent AF in 14 (14%), each of whom had mitral valve disease. Patients with other underlying pathology had complete recovery of atrial rhythm. A normal-sized A wave was detected in 88% for transtricuspid flow and in 73% for transmitral flow, suggesting concomitant recovery of atrial contraction. Among 36 patients without mechanical valves, 30 (83%) with atrial rhythm and contraction have been taken off anticoagulation therapy, including 10 who are free of all medication. CONCLUSIONS The results suggest that the combined approach is safe, effective, and indicated in patients who are judged capable of tolerating the procedure and likely to regain atrial rhythm.

Twelve years' experience with the St. Jude Medical valve prosthesis

Since July 1978, 1,284 patients have received the St. Jude Medical prosthesis (425 aortic, 636 mitral, and 223 double aortic-mitral), and the results in these patients were reviewed according to guidelines of the Society of Thoracic Surgeons. Follow-up was complete in 98%. Of 80 late deaths, 29% were valve related. The actuarial survival rate, including operative deaths, at 12 years was 81.7% and 87.1%, respectively, for aortic and mitral valve replacement, and it was 82.6% at 11 years after double valve replacement. All patients were anticoagulated with warfarin to maintain the thrombotest value between 10% and 25%, which is equivalent to between 2.8 and 1.6 times the control according to the international normalized ratio of the prothrombin time. The linearized rate of complication for aortic, mitral, and double valve replacement, respectively (expressed as the percent per patient-year), was as follows: structural deterioration, 0; non-structural dysfunction, 0.16, 0.30, and 0.20; valve thrombosis, 0.05, 0.09, and 0; thromboembolism, 1.35, 1.63, and 0.79; anticoagulant-related hemorrhage, 0.10, 0.18, and 0.10; and prosthetic valve endocarditis, 0.21, 0.06, and 0.20. Reoperation was performed in 16 patients. The freedom from reoperation rate at 12 years was 99.5% and 98.0% for aortic and mitral valve replacement, respectively, and it was 99.1% at 11 years for double valve replacement. Thus, during the 12-year follow-up in patient who received the St. Jude Medical prosthesis, the valve performed satisfactorily and with an acceptable risk of late complication even though patients were anticoagulated using a lower dose of warfarin.

Improved success rate of the maze procedure in mitral valve disease by new criteria for patients’ selection

OBJECTIVE We have carried out the maze procedure for atrial fibrillation (AF) as a combined operation with mitral valve surgery in a consecutive fashion until December 1994 (period 1). Therefore, the success rate in sinus rhythm conversion remained unsatisfactory. We have selected the patients according to arbitrarily decided new criteria since January 1995 (period 2), and examined the results prospectively. METHODS Between May 1992 and February 1997, we carried out the maze procedure in 220 patients as a combined operation with mitral valve surgery. During period 2, we carried out the maze procedure in 63 cases who satisfied all the new criteria (voltage of f-wave in V1 lead > 0.1 mV, cardiothoracic ratio (CTR) < 70%, LA dimension < 70 mm), and 37 patients out of these criteria. Success was defined as sinus rhythm restoration without sick sinus syndrome. RESULTS There were 4 hospital deaths (1.8%) and 4 late deaths (1.8%). Success rate was significantly (P = 0.0089) higher in period 2 (82%) than in period 1 (65%). Success rate was significantly higher in patients within criteria than out of criteria both in period 1, period 2, and total (77 versus 48%, P = 0.018; 90 versus 66%, P = 0.004, and 83 versus 55%, P = 0.0001). CONCLUSION The maze procedure is highly reliable when combined with mitral valve surgery if patients are selected properly.

Surgical Treatment of Behcet's Disease Involving Aortic Regurgitation

BACKGROUND Behçets disease involving aortic regurgitation is rare, and prosthetic valve detachment after aortic valve replacement is one of the most serious complications reported. We investigated the surgical results in 10 patients with aortic regurgitation caused by Behçets disease. METHODS Between 1981 and 1997, 10 patients with aortic regurgitation secondary to Behçets disease had surgery. There were 8 men and 2 women, and their ages ranged from 33 to 60 years (mean, 46+/-8 years). The surgical procedures for aortic regurgitation were aortic valve replacement in 6 patients and Bentall type operation in 4. RESULTS No patient died during the hospital stay. The follow-up periods ranged from 11 to 185 months (mean, 87 months). Two patients died during the follow-up period. The acturial survival rate was 89% at 5 years and 67% at 10 years. Prosthetic valve detachment or suture detachment requiring redo operation occurred in 4 patients, 3 of whom had redo operations twice. Four patients had a composite graft replacement, and 1 patient died after the operation. No prosthetic valve detachment was noted in 64% of the patients at 5 years and in 43% at 10 years. CONCLUSIONS The rate of prosthetic valve detachment was 40% (4 of 10 patients), with a higher incidence in patients with Behçets disease than in those treated during the same period at the same hospital for aortitis caused by other diseases. Surgical techniques for treatment of this condition should be modified to improve the surgical outcome in these patients.

Ten-year experience with the Carpentier-Edwards pericardial xenograft in the tricuspid position.

We reviewed the cases of 66 patients who underwent 67 tricuspid valve replacements with Carpentier-Edwards pericardial xenografts between April 1985 and January 1994. Average patient age at time of operation was 52 years (range 8 to 71 years). Concomitant mitral or aortic valve replacements were performed in 46 patients. There were 10 operative deaths and 6 late deaths. Actuarial survival at 9 years was 75.4% +/- 5.7%. Prosthetic valve endocarditis occurred twice in one patient. Reoperations for tricuspid regurgitation and for concomitant procedures (maze operation and repair for leak of the mitral prosthesis) were performed in two patients. In both cases, examination of the explanted prostheses showed that the tricuspid regurgitation was the result of nonstructural dysfunction caused by fibrous pannus formation on the cusps of the ventricular side. Among the survivors, 47 patients (92%) were in functional class I or II. Prosthetic valve function was studied by color Doppler echocardiography. Among 38 patients, tricuspid regurgitation more than grade 3/4 or transprosthetic gradient more than 5 mm Hg was found in 11. One patient had right heart failure and the others had no symptoms. In 10 years of experience with the Carpentier-Edwards pericardial xenograft, mortality and morbidity after tricuspid valve replacement were satisfactory. Echocardiographic examination revealed subclinical prosthetic dysfunction in 35% of patients who were followed up for longer than 5 years, however, and we believe that these patients should receive careful follow-up.

Changes in diastolic function during development and correction of chronic LV volume overload produced by mitral regurgitation.

Background. Mitral regurgitation (MR) causes an augmentation in left ventricular (LV) diastolic function, increasing early diastolic filling rate and decreasing LV stiffness. Whether these changes in diastolic function persist, return to normal, or become abnormal after mitral valve replacement (MVR) is unknown. Methods and Results. Simultaneous LV echocardiography and catheterization studies were performed in six dogs in the baseline state (baseline), 3 months after creation of MR (chronic MR), and 3 months after MVR. Chronic MR caused LV dilation (end‐diastolic dimension increased from 4.5 ±0.1 cm in baseline to 5.8±0.1 cm in chronic MR, p<0.05) and eccentric LV hypertrophy (LV‐to‐body weight ratio increased from 3.6±0.2 g/kg in baseline to 4.9±0.4 g/kg in chronic MR, p<0.05). Chronic MR caused an increase in LV early diastolic filling rate (peak rate of increase in minor‐axis dimension increased from 11±1 cm/sec in baseline to 18±1 cm/sec in chronic MR, p<0.05), did not change the time constant of myocardial relaxation (&rgr; was 31 ± 4 msec in baseline and 30±2 msec in chronic MR), and caused a decrease in the modulus of regional chamber stiffness from 7.7±1.2 in baseline to 2.4±0.03 in chronic MR,p<0.05. MVR caused the resolution of LV dilation (end‐diastolic dimension returned to normal [4.8±0.2 cm]), but three months after MVR, regression of LV hypertrophy was incomplete (LV‐to‐body weight ratio remained elevated [4.4±0.5 g/kg]). After MVR, LV early diastolic filling rate (8±1 cm/sec), the relaxation time constant (31±2 msec), chamber stiffness (7.1 ±1.8), myocardial stiffness (11.2±3.1), and LV end‐diastolic pressure (8±1 mm Hg) returned to normal. Conclusions. The enhanced diastolic function seen in chronic MR returned to normal after correction of the chronic volume overload by MVR. (Circulation 1993;87:1378‐1388)

Surgical Management of Behçet’s Aortitis: A Report of Eight Patients

BACKGROUND Behçets aortitis is one of the most severe manifestations of Behçets disease. However, there have been few reports of this rare entity. This article we describe our experience with surgical treatment of Behçets aortitis in 8 patients. METHODS From May 1978 to February 1995, we operated on 8 patients with Behçets aortitis. All patients were followed up for a total of 54.4 patient-years (mean, 6.8 years). RESULTS There were no operative deaths, but 1 patient died in the hospital of ventricular fibrillation. Another death occurred as a result of pseudoaneurysm rupture 10 months after operation. Fourteen operations were performed on eight patients: a second operation was performed on four patients, and a third operation was performed on two patients. The translocated Bentall procedure, a modified Bentall procedure, was performed six times. One patient required a second operation for graft detachment, but the others have done well without further surgical intervention. Aortic valve replacement was performed six times, and three reoperations were needed after aortic valve replacement. CONCLUSIONS The translocated Bentall procedure may be effective for Behçets aortitis, but further investigation is necessary.

Tricuspid valve replacement with bioprostheses: long-term results and causes of valve dysfunction

BACKGROUND Although the clinical performance of bioprostheses after valve replacement in the aortic and mitral position has been reported, little is known of the performance of tricuspid bioprostheses. The mechanism of bioprosthetic valve dysfunction after tricuspid valve replacement (TVR) is not clear. METHODS We reviewed 98 cases of TVR with bioprostheses. To clarify the causes of valve dysfunction, pathologic examination of the explanted valve at the reoperation was performed. RESULTS Actuarial survival at 18 years was 68.7% +/- 5.8%. There were 12 redo TVRs. In six of the 12 cases, isolated redo TVR was performed. In the other cases, concomitant cardiac procedures were performed. The causes of prosthetic valve dysfunction were pannus formation on the cusps of the right ventricle side (four cases), native valve attachment (two cases), pannus formation + native valve attachment (two cases), sclerotic change (one case), pannus formation + sclerotic change (one case), and native valve attachment + valve infection (one case). Freedom from reoperation, structural valve deterioration, and nonstructural dysfunction at 18 years was 62.7% +/- 10.7%, 96.0% +/- 2.9%, and 76.7% +/- 8.3%, respectively. CONCLUSIONS In our 18 years of experience, although the survival after TVR with bioprostheses is acceptable, the reoperation free rate is not satisfactory. Pannus formation on the cusps of the ventricular side seems to be a serious problem that causes bioprosthetic dysfunction in the tricuspid position.

Regional work of the human left ventricle calculated by wall stress and the natural logarithm of reciprocal of wall thickness

Regional left ventricular work is a more precise indicator of function than is simple shortening fraction. Regional work of the ventricle normalized to a unit volume of myocardium (RWM) is given by the following equation: RWM = - intergral of sigma d[ln(1/H)], where sigma is the mean wall stress and ln(1/H) is the natural logarithm of reciprocal of wall thickness. This method has been previously validated in animal experiments and it is now extended to the clinical setting for the first time. In 10 normal subjects and 6 patients with anteroseptal myocardial infarction, ventricular minor axis and wall thickness were measured by echocardiography and recorded simultaneously with high fidelity left ventricular pressure. Then, regional work of the interventricular septum and of the posterior wall of the left ventricle was calculated from the measured pressure and dimension data. In normal subjects, regional work of the septum and posterior wall was 6.1 +/- 1.7 and 7.0 +/- 1.8 mJ/cm3, respectively; the average of the septal and posterior wall regional work multiplied by the left ventricular myocardial volume correlated well (r = 0.93) with the total mechanical work done by the entire left ventricle. In patients with anteroseptal infarction, septal regional work was greatly reduced (0.6 +/- 1.7 mJ/cm3), compared with posterior wall regional work in the same patients (6.1 +/- 1.8 mJ/cm3). This simple method can be applied clinically in assessing the functional state of different regions of the myocardium.